Pressure-responsive valves



March 10, 1959 E.` E. sHuBE 2,876,788

PRESSURE-RESPONSIVE VALVES l Filed Aug. 16, 1956 lNvENToR EUGENE ELLIOT sHuBE E, .Bmwaw HIS ATTORNEYS .United States Patent-O 2,876,788 PRESSURE-RESPONSIVE VALVES Eugene Elliot Shuhe, Elmont, N. Y., assgnor to Fairchild Engine and Airplane Corporation, Hagerstown, Md., a corporation of Maryland Application August 16, 1956, Serial No. 604,383

' 6 claims. (cl. 137-112) This invention relates to improvements in valves and it pressure-responsive valve which is suitable for use as an exhaust valve in pneumatic systems including pneumatically driven motors.

In systems of the type disclosed in my copending application Serial No. 604,461, tiled August 16, 1956, I have disclosed a pneumatic actuator system in which a lobe type or screw type motor is used for actuating a screw-type jack for moving a reciprocable or oscillatable member. The system may include' a selector valve by means of which the direction of rotation of the motor is controlled and a follow-up control tocause a related operation of the motor and displacement of the driven element. The system disclosed therein also includes a valve of the type embodying the present invention as the exhaust valve of the pneumatic system. In the system disclosed in the aforesaid application, the new valve finds particular utility for the reason that it can be of the size best suited for avoiding the development of back pressure in the system and Venabling the fast discharge of large volumes of exhaust gases from the motor.

More particularly, the new valve is a double acting valve which is responsive to pressures in the system on opposite sides of the motor, namely, high pressure feed air and low pressure exhaust air, the valve being displaceable by the high pressure air to open it and allow the escapev of the exhaust gases freely fromy the motor. Inasmuch as the valve is responsive to gas or air pressure in the system and is independent of the size of the motor and the selector valve by means of which the operation of the motor is controlled, the valve can be designed and constructed to t within the available space in a system and to give maximum freedom of llow gas therethrough.

For a better understanding of the present invention reference may be had to the accompanying drawings in which:

Figure 1 is a schematic illustration of a system involving a control valve, a motor under the control of the control valve and an exhaust valve of the type embodying the present invention;

Figure 2 is a View in section through my new exhaust valve illustrating the valve in its neutral position; and

Figure 3 is a view in section showing the exhaust valve in one of its two exhaust positions.

As shown in Figure 1, a typical system in which the valve embodying the present invention may be used includes a three-port selector valve connected with a pressure pipe 11 through which air or other gas under pressure is supplied to the valve and having two system ports 12 and 13, each connected by means of pipes 14 and 15 to opposite ports of a lobe motor 16. A lobe type of motor has a ypair of rotors each having a plurality of meshing compressor lobes. Such motors can be and have been used heretofore as superchargers and can be operated at widely varying speeds either to supply power or to supply gas at positive superatmospheric relates more particularly to an improved form of 'a' v 2,876,788 Patented Mar. 10, 1959 pressure. The pipe 14 is provided with a branch conduit 17 which communicates with one port 18 of the new pressure-responsive valve 19 embodying the present invention. A branch conduit 20 also connects the pipe 15 to another port 21 of the exhaust valve 19. As shown in Figures 2 and 3, the valve 19 includes a hollow casing 22 having a transverse partition 23 supporting a generally circular shroud 24. The shroud is provided with a tubular exhaust port or passage 25 which extends through the end wall 26 ofthe casing 22. The partition 23 extends around the shroud and is joined at its outer periphery to the casing 22 thereby dividing the casing into two passages 27 and 28 on opposite sides of the partition, the passage 27 communicating with one end of the shroud 24 andthe conduit 20 through the port 21 and the passage 28 communicating with the other end of the shroud 24 and conduit 17 through the port 18.

A bar 30 extends substantially diametrically across the shroud and serves to support and guide a valve stem 31 for sliding movement through `the bar. Circular valve heads 32 and 33 are mounted on opposite ends of the stem and t within the shroud, thereby substantially closing its opposite ends. Springs 34 and 35 are interposed between the bar 30 and the valve head 32 and the bar 30 and the valve head 33, respectively, to normally bias the valve into a neutral position as shown in Figure 2 in which both of the valve heads are disposed within the shroud 24. Valve seats 36 and 37 of generally annular shape are formed within the shroud on opposite sides of the exhaust port 25 for cooperation with the valve heads 32 and 33, respectively.

The valve 19 operates in the following manner. Assuming that pressure is supplied to the supply pipe 11 and the valve 10 is operated so that'the fluid is supplied to the pipe 15, the motor 16 will be driven in one direction and the gases expanded through the motor will pass through the exhaust pipev 14 into the branch conduit 17 and through the port 18 into the passage 28. Inasmuch as the passage 27 communicates by means of the conduit 20 with the pipe 15 which supplies the gas under pressure to the motor, the passage 27 will be at a higher pressure than the passage 28 which receives the exhaust air under pressure through the pipe 15. After equalization of the pressures in the passages 27 and 28, the valve will be restored to its neutral position.

lf the valve 10 is actuated to supply air under pressure through the port 12, high pressure air will be introduced into the passage 28 of the valve, while the exhaust air will enter the passage 27 through the branch conduit 20. Accordingly, the valve head 33 will be subjected to a higher pressure than the valve head 32 so that the valve head is forced against its seat 37 and the valve head 32 is displaced from the end of the shroud 24 to allow the exhaust air to escape from the conduit 20 to the passage 27 and through the vent 25 to atmosphere. Due to the relatively large size of the port area provided by a valve of the type described, it is possible to vent large volumes of air or other gases without building up a substantial back pressure in a system. Moreover, inasmuch as the valve is responsive to the gas pressure of a system and not the exhaust gas pressure, it opens promptly thereby overcoming any tendency of the motor to fail to respond promptly.

It will be understood that the pressure-responsive valve 19 described. herein can be. large or small,` dependingupon the volume and rate of flow of the gases to be handled thereby and that the shape and arrangement of the valve heads and valve seats and the type of valve hea-ds and seats may be modified very widely.

Moreover, the valve itself may be made of substantially any kind of material such as plastic or metal depending uponv environment in which it is to be used.

From the preceding description of a typical embodiment of the invention, it is apparent that the valve is susceptible to considerable modification in its size, arrangement and use, and accordingly, the form of the valve described'herein should be considered as illustrative.

l. A pressure-responsive valve comprising a casing having a pair of passages therein, a tubular member having open opposite ends, each end communicating with one of said passages, said tubular member having an exhaust passage between its ends, a valve member movable substantially axially of said tubular member and having valve heads fixed at its opposite ends spaced apart a lesser distance than the length of said tubular member, means biasing said valve member to a position in which both valve heads are within said tubular member and substantially closing both of its ends to disconnect both of said passages from said exhaust passage, said valve member being movable by a higher pressure in one of said passages than in the other passage to displace one of said heads out of the tubular member to connect the other passage to said exhaust port, said biasing means opposing movement of said valve.

2. The valve set forth in claim l comprising valve seats for said valve heads within said tubular member on opposite sides of said exhaust passage and spaced from said heads when. both are within said tubular member.

3. The valve set forth in claim. l comprising valve seats adjacent to opposite ends of said valve member for engagement with the other of said valve heads when said one head is displaced out of the tubular member.

4. A pressure-responsive valve comprising a casing having a pair of passages therein, a tubular shroud member having open opposite ends each end communicating with one of said passages, said shroud member having an exhaust port between its ends, a valve member mounted in said shroud member and having a valve stem extending substantially axially of said shroud member and valve heads iixed at its opposite endsmeans supporting said valve member for movement axially of said shroud member between a rst position in which both of said valve heads are within said shroud member and said passages are substantially disconnected from said exhaust port and second positions in which one of said heads is disposed outwardly of said shroud member to connect one of said passages with said exhaust port and the other head is within the shroud member, valve seats in said shroud member on opposite sides of said exhaust port and spaced from said valve heads when the valve member is in said iirst position and one of said valve seats engaging one of saidk valve heads in one of said second positions, and means normally biasing said valve member to said iirst position and opposing movement of said valve member to said second position.

5. A pressure-responsive valve comprising a casing having a pair of passages therein, a tubular member havp ing open opposite ends,'each end communicating with one of said passages, said tubular member having an exhaust port between its ends, a valve member movable axially of said tubular member and having opposite ends tting in said tubular member and substantially closing the'open ends thereof, said valve member being movable from a lirst position in which said opposite ends are disposed within said casing by gas pressure in one of said passages to a second position in which one of said ends is outside said tubular member and .the other of said passages is in communication with said exhaust port, and means biasing said valve member to said iirst position and opposing movement of said valve member to said second position.

6. The valve set forth in claim 5 comprising valve seats in said tubular member on opposite sides of said exhaust port, one of said valve seats being in sealing en gagement with the other end of said valve member when the latter is in said second position.

References Cited in the tile of this patent UNITED STATES PATENTS 

